yep,but see the thing is you need to achieve 3 things in order to get appstore, and all other "MAC ADRESS" related softwares,
first you need to get it working, this first and most important stage, it must work, not just recognized. (i myself, since experiencing KP with the modded Driver for my Atheros L1 LAN, bought a chip PCI card with 8169 chip to have working LAN)
step 2 is to make the interface recognized as built-in, you have 3 ways doing it, DSDT injection (DSM method), EFI string (Device-properties in boot.plist), and to turn on the EthernetBuiltIn switch on chameleon (or any other boot-loader with this option)
last thing to check is that the OS recognize the interface as the first in the chain (en0). this way, all request for MAC address authentications goes to this interface, which is "built-in".
some reporting however that for instance EthernetBuiltIn didn't work for them but EFI string did (can't understand that but whatever...), so it's best to try everything.
if it's still refuse to work, you can try do the same as me and buy a chip ethernet card (with support ) and if that the only problem between you and appstore then you will be fine (however if everything i said you already done, then you might need to look somewhere else, or try to understand, by the modification you are doing to make the installation work, which might be the problem)
hope this will help you solve it